1. Field of the Invention
The present invention relates to an automatic transmission wherein rotation of a clutch from drag torque can be stopped by operation of a brake in neutral.
2. Description of the Related Art
The automation transmission depicted in FIG. 2 of Japanese Unexamined Patent Application Publication (“Kokai”) NO. 2001-182785 provides eight speeds (“gears” or “gear ratios”), and includes an input rotary member which is continuously rotated by an engine even while the transmission is in neutral, and that continuous rotation is transmitted to one of the sets of frictional engagement elements (clutch plates) of a third clutch C3 and a fourth clutch C4 via a first planetary gear set G1. Therefore, drag torque is generated between the clutch plates and the clutch discs, interleafed therewith and linked to a first shaft J1 (intermediate rotary member), whereby the clutch and the first shaft J1 are rotated at the rotational speed Nd by this drag torque.
In shifting from the above-described neutral state into reverse by controlling the rotation of the first shaft J1 with application of brake pressure, while holding a second shaft element J2 in a fixed state, a sun gear S2 of a Ravigneaux-type gear unit G23 is rotated by the drag torque. Since a third shaft J3 is fixed by the vehicle brake, the braking of carriers PC2 and PC3 while a ring gear R2 is fixed, causes the output torque Tout to fluctuate, whereby shift shock is generated to the discomfort of the driver.